You claim the amount you earned while living in Illinois.  You will file a part-year return for Illinois, and allocate, apportion, or designate, the amount of income you earned while living in Illinois if it is not clearly stated on your W-2.  Your employer may have this information, or you can use percentages.  You may calculate what percent of the year you lived in Illinois, and then multiply your income earned from that company by this percentage.  You will need to pay tax to the new state you moved to on the remaining portion of that income and file a part-year return with that state as well unless you moved to a state that does not have state income tax.